Review Advances in biomass transformation to 5-hydroxymethylfurfural and mechanistic aspects Saikat Dutta a, **, Sudipta De b , Basudeb Saha b, * a Department of Chemistry, University of Florida, Gainesville, FL 32611, USA b Laboratory of Catalysis, Department of Chemistry, University of Delhi, Delhi 110 007, India article info Article history: Received 25 October 2011 Received in revised form 30 January 2013 Accepted 3 February 2013 Available online 26 March 2013 Keywords: Biomass Cellulose Lignocellulosics Dehydration mechanism Sustainable chemistry abstract Biomass-derived 5-hydroxymethylfurfural (HMF) has been emerged as a key platform chemical for the production of fine chemicals and liquid fuels. The direct transformation of cellulose and lignocellulosic biomass into HMF in ionic liquids and organic solvents is most desired in terms of process economics and sustainability. The focus of this review is purely on the HMF production from cellulose and lignocelluloses and mechanistic aspects of HMF formation in order to bridge the gap in understanding the factors responsible for selective conversion and selection of catalyst. Additionally, present review is devoted exclusively to the latest developments, namely microwave-assisted degradation of cellulose to HMF, application of solid acid and ionic-liquid catalysis to address their effectiveness for HMF production. Approaches for the cellulose transformation into HMF are especially empha- sized in order to explore newer avenues of biomass as renewable feedstock for energy and chemicals. ª 2013 Elsevier Ltd. All rights reserved. 1. Introduction The ever increasing global demand for energy coupled with a finite oil supply not only dramatically volatilizes the oil prices but also challenges economic and industrial security world- wide [1,2]. Continued reliance on petroleum feedstock will lead to an unacceptable amount of greenhouse gas emissions which has been the major concern [3]. Since the global con- sumption of the liquid petroleum tripled in the ensuing years [4], researchers and policy-makers have given priority to explore alternative feedstock to avoid the most unfortunate scenarios of energy crisis in future. Much of this attention has been directed at liquid biofuels and in particular, biomass feedstock which has been utilized as source for liquid biofuels and hydrocarbons [5]. In this context, biomass-derived bio- fuels feature tremendous potentials as renewable energy. Biomass represents an abundant carbon-neutral renewable resource and its enhanced use would address several chal- lenges. Advances in process chemistry leading to a new manufacturing concept for converting renewable biomass- derived carbohydrates and biomasses into valuable chem- icals and liquid fuels, offers the total sustainability that will lead to a new manufacturing paradigm [6]. It is estimated that after about 15 years, up to 30% of raw materials for the chemical industry will be produced from renewable biomass [7]. The products from renewable resources (fiber composite materials, starch- and protein-derived prod- ucts) are already available in the market [8]. Current chemical * Corresponding author. Tel.: þ91 011 2766 6646; fax: þ91 011 2766 7794. ** Corresponding author. E-mail address: bsaha@chemistry.du.ac.in (B. Saha). Available online at www.sciencedirect.com http://www.elsevier.com/locate/biombioe biomass and bioenergy 55 (2013) 355 e369 0961-9534/$ e see front matter ª 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.biombioe.2013.02.008